leading axle forks?

Why does my LTD have the axle on the front of the fork tubes, where just about every other bike I look at has the axle on the bottom of the tube?

My KZ750H [LTD] bikes have the leading axle as well. That, plus the increased stearing head rake makes the handling much more highway (or drag strip) stable at the top end. My KZ750E [Standard] has the lesser rake and the axles at the base of the forks, and is much more responsive in the twisties.

My Z550 has the leading axle type, and my Gpz550 has a center axle fork. I think that apeman is right, the Z550 being a compromise between those two examples (leading axle but less rake than the LTDs)

My KZ750H [LTD] bikes have the leading axle as well. That, plus the increased stearing head rake makes the handling much more highway (or drag strip) stable at the top end. My KZ750E [Standard] has the lesser rake and the axles at the base of the forks, and is much more responsive in the twisties.

Actually, the leading axle (assuming the same triple clamps, and therefore the same triple clamp offset) would decrease the trail, making the steering quicker. If the bike with the leading axle fork tubes has more rake, the leading axles would just lessen the increased trail due to increased rake. Got that?
I think the leading axle was a way to minimize the effect of the increased rake, while still giving the "chopper" look. The ergonomics of the bikes (where the rider's hands, feet, and butt interact with the bike) is probably the difference in the perceptions of quickness. For instance, my GPz1100 has a whopping 29 degrees of rake, where the standard had (IIRC) 26 degrees. Which one do you think is more fun in the twisties?

This is an interesting question. And I'm interested in the answers and opinions.
My 1982 kz750H project bike is supposed to have leading axle forks, but has the forks with axles on the bottom.
I've only ridden it at about 30MPH since it has crappy old tires on it, so I can't say how it handles...yet.
Somebody has obviously swapped the forks out awhile ago, and I wonder if it will help or hinder the steering.
:huh:

Mariozappa and pstrbrc,

Your posts interest me, since I clearly have a limited understanding of steering geometry. I thought (wrongly, I guess), that the increased linear distance between the steering head and the axle made the bike less responsive (and more stable at high speeds) in steering. Both the leading axle and the greater steering head angle contribute to this increase in distance. What is it that I have misunderstood.

Mariozappa, I was thinging about putting the forks from a KZ750E on my KZ750H [LTD]. The E model has the axle on the fork bottom. It sounds like you have this setup, so I would like to hear how it works after you get your bike in top shape. I THOUGHT it would make my LTD more responsive in the turns, like the E model is. Fellow KZriders, am I wrong about this????

Apeman,
I let you know how it works out.
I've seen the 900 and 100 LTD without the leading axle that came from the factory, but I don't know what the difference in the rake is.
Back to looking at the specs.
:S

pstrbrc is right. the leading axle and raked trple trees are ways to reduce trail in those long chopper front ends. that little bit makes a big difference in trail figgures. most trail numbers are from 3.5 to 6 inches of trail.

the comment about rake is not always to correct way to guess how a bike will handle in the twistys. trail is a line that goes thought the neck stem to the ground and a line that goes though the axle to the ground. the distance between those two points is your trail. longer the trail the more stable the bike is at speed and it wants to go in a straight line but a slow speeds you get what chopper folk call wheel flop. the shorter trail numbers you see in sport bikes account for the snap handling and response that you need in a sport bike.

For those of you who would like a basic primer in motorcycle suspension, here's a link:
www.carbibles.com/suspension_bible_bikes.html
It's written by a car guy, so it's not nearly as complete as some of my textbooks on my shelf (I haven't always been a minister, I was a beer-drinking engineer in another life :blush: ) but what's there is good.